Pasteur looked, then suddenly saw the magnificent ingeniousness of this little experiment. “Why, then microbes can’t fall into the flask, because the dust they stick to can’t very well fall upward—marvelous! I see it now!”

“Exactly,” smiled Balard. “Try it and find out if it works—see you later,” and he left to continue his genial round of the laboratories.

Pasteur had bottle washers and assistants now, and he ordered them to hurry and prepare the flasks. In a moment the laboratory was buzzing with the stuttering ear-shattering b-r-r-r-r-r of the enameler’s lamps; he fell to work savagely. He took flasks and put yeast soup into them and then melted their necks and drew them out and curved them downward—into swan’s necks and pigtails and Chinaman’s queues and a half-dozen fantastic shapes. Next he boiled the soup in them—that drove out all the air—but as the flasks cooled down new air came in—unheated air, perfectly clean air.

The flasks ready, Pasteur crawled on his hands and knees, back and forth with a comical dignity on his hands and knees, carrying one flask at a time, through a low cubby hole under the stairs to his incubating oven. Next morning he was first at the laboratory, and in a jiffy, battered notebook in his hand, if you had been there you would have seen his rear elevation disappearing underneath the stairway. Like a beagle to its rabbit Pasteur was drawn to this oven with its swan neck flasks. Family, love, breakfast, and the rest of a silly world no longer existed for him.

Had you still been there a half hour later, you would have seen him come crawling out, his eyes shining through his fogged glasses. He had a right to be happy, for every one of the long twisty necked bottles in which the yeast soup had been boiled was perfectly clear—there was not a living creature in them. The next day they remained the same and the next. There was no doubt now that Balard’s scheme had worked. There was no doubt that spontaneous generation was nonsense. “What a fine experiment is this experiment of mine—this proves that you can leave any kind of soup, after you’ve boiled it, you can leave it open to the ordinary air, and nothing will grow in it—so long as the air gets into it through a narrow twisty tube.”

Balard came back and smiled as Pasteur poured the news of the experiment over him. “I thought it would work—you see, when the air comes back in, as the flask cools, the dusts and their germs start in through the narrow neck—but they get caught on the moist walls of the little tube.”

“Yes, but how can we prove that?” puzzled Pasteur.

“Just take one of those flasks that has been in your oven all these days, a flask where no living things have appeared, and shake that flask so that the soup sloshes over and back and forth into the swan’s neck part of it. Put it back in the oven, and next morning the soup will be cloudy with thick swarms of little beasts—children of the ones that were caught in the neck.”

Pasteur tried it, and it was so! A little later at a brilliant meeting where the brains and wit and art of Paris fought to get in, Pasteur told of his swan neck flask experiment in rapturous words. “Never will the doctrine of Spontaneous Generation recover from the mortal blow that this simple experiment has dealt it,” he shouted. If Balard was there you may be sure he applauded as enthusiastically as the rest. A rare soul was Balard.

Then Pasteur invented an experiment that was—so far as one can tell from a careful search through the records—really his own. It was a grand experiment, a semi-public experiment, an experiment that meant rushing across France in trains, it was a test in which he had to slither around on glaciers. Once more his laboratory became a shambles of cluttered flasks and hurrying assistants and tinkling glassware and sputtering, bubbling pots of yeast soup. Pasteur and his enthusiastic slaves—they were more like fanatic monks than slaves—were getting ready hundreds of round bellied bottles. They filled each one of them part full of yeast soup and then, during many hours that shot by like moments—such was their excitement—they doused each bottle for a few minutes in boiling water. And while the soup was boiling they drew the flask necks out in a spitting blue flame until they were sealed shut. Each one of this regiment of bottles held boiled yeast soup—and a vacuum.

Armed with these dozens of flasks, and fussing about them, Pasteur started on his travels. He went down first into the dank cellars of the Observatory of Paris, that famous Observatory where worked the great Le Verrier, who had done the proud feat of prophesying the existence of the planet Neptune. “Here the air is so still, so calm,” said Pasteur to his boys, “that there will be hardly any dust in it, and almost no microbes.” Then, holding the flasks far away from their bodies, using forceps that had been heated red hot in a flame, they cracked the necks of ten of the flasks in succession; as the neck came off each one, there was a hissing “s-s-s-s” of air rushing in. At once they sealed the bottles shut again in the flickering flame of an alcohol lamp. They did the same stunt in the yard of the observatory with another ten bottles, then hurried back to the little laboratory to crawl under the stairs to put the bottles in the incubating oven.

A few days later Pasteur might have been seen squatting before his oven, handling his rows of flasks lovingly, laughing his triumph with one of those extremely rare laughs of his—he only laughed when he found out he was right. He put down tiny scrawls in his notebook, and then crawled out of his cubby-hole to tell his assistants: “Nine out of ten of the bottles we opened in the cellar of the Observatory are perfectly clear—not a single germ got into them. All the bottles we opened in the yard are cloudy—swarming with living creatures. It’s the air that sucks them into the yeast soup—it’s the dust of the air they come in with!”

He gathered up the rest of the bottles and hurried to the train—it was the time of the summer vacation when other professors were resting—and he went to his old home in the Jura mountains and climbed the hill of Poupet and opened twenty bottles there. He went to Switzerland and perilously let the air hiss into twenty flasks on the slopes of Mont Blanc; and found, as he had hoped, that the higher he went, the fewer were the flasks of yeast soup that became cloudy with swarms of microbes. “That is as it ought to be,” he cried, “the higher and clearer the air, the less dust—and the fewer the microbes that always stick to particles of the dust.” He came back proudly to Paris and told the Academy—with proofs that would astonish everybody!—that it was now sure that air alone could never cause living things to rise in yeast soup. “Here are germs, right beside them there are none, a little further on there are different ones ... and here where the air is perfectly calm there are none at all,” he cried. Then once more he set a new stage for possible magnificent exploits: “I would have liked to have gone up in a balloon to open my bottles still higher up!” But he didn’t go up in that balloon, for his hearers were already sufficiently astonished. Already they considered him to be more than a man of science; he became for them a composer of epic searchings, a Ulysses of microbe hunters—the first adventurer of that heroic age to which you will soon come in this story.

Many times Pasteur won his arguments by brilliant experiments that simply floored every one, but sometimes his victories were due to the weakness or silliness of his opponents, and again they were the result of—luck. Before a society of chemists Pasteur had insulted the scientific ability of naturalists; he was astonished, he shouted, that naturalists didn’t stretch out a hand to the real way of doing science—that is, to experiments. “I am of the persuasion that that would put a new sap into their science,” he said. You can imagine how the naturalists liked that kind of talk; particularly Mr. Pouchet, director of the Museum of Rouen, did not like it and he was enthusiastically joined in not liking it by Professor Joly and Mr. Musset, famous naturalists of the College of Toulouse. Nothing could convince these enemies of Pasteur that microscopic beasts did not come to life without parents. They were sure there was such a thing as life arising spontaneously; they decided to beat Pasteur on his own ground at his own game.

Like Pasteur they filled up some flasks, but unlike him they used a soup of hay instead of yeast, they made a vacuum in their bottles and hastened to high Maladetta in the Pyrenees, and they kept climbing until they had got up many feet higher than Pasteur had been on Mont Blanc. Here, beaten upon by nasty breezes that howled out of the caverns of the glaciers and sneaked through the thick linings of their coats, they opened their flasks—Mr. Joly almost slid off the edge of the ledge and was only saved from a scientific martyr’s death when a guide grabbed him by the coat tail! Out of breath and chilled through and through they staggered back to a little tavern and put their flasks in an improvised incubating oven—and in a few days, to their joy, they found every one of their bottles swarming with little creatures. Pasteur was wrong!

Now the fight was on. Pasteur became publicly sarcastic about the experiments of Pouchet, Joly and Musset; he made criticisms that to-day we know are quibbles. Pouchet came back with the remark that Pasteur “had presented his own flasks as an ultimatum to science to astonish everybody.” Pasteur was furious, denounced Pouchet as a liar and bawled for a public apology. It seemed, alas, as if the truth were going to be decided by the spilling of blood, instead of by calm experiment. Then Pouchet and Joly and Musset challenged Pasteur to a public experiment before the Academy of Sciences, and they said that if one single flask would fail to grow microbes after it had been opened for an instant, they would admit they were wrong. The fatal day for the tests dawned at last—what an interesting day it would have been—but at the last moment Pasteur’s enemies backed down. Pasteur did his experiments before the Commission—he did them confidently with ironical remarks—and a little while later the Commission announced: “The facts observed by Mr. Pasteur and contested by Messrs. Pouchet, Joly and Musset, are of the most perfect exactitude.”

Luckily for Pasteur, but alas for Truth, both sides happened to be right. Pouchet and his friends had used hay instead of yeast soup, and a great Englishman, Tyndall, found out years later that hay holds wee stubborn seeds of microbes that will stand boiling for hours! It was really Tyndall that finally settled this great quarrel; it was Tyndall that proved Pasteur was right.

V

Pasteur was now presented to the Emperor Napoleon III. He told that dreamy gentleman that his whole ambition was to find the microbes that he was sure must be the cause of disease. He was invited to an imperial house party at Compiègne. The guests were commanded to get ready to go hunting, but Pasteur begged to be excused; he had had a dray load of apparatus sent up from Paris—though he was only staying at the palace for a week!—and he impressed their Imperial Majesties enormously by bending over his microscope while everybody else was occupied with frivolous and gay amusements.

The world must know that microbes have got to have parents! At Paris he made a popular speech at the scientific soirée at the Sorbonne, before Alexandre Dumas, the novelist, and the woman genius, George Sand, the Princess Mathilde, and a hundred more smart people. That night he staged a scientific vaudeville that sent his audience home in awe and worry; he showed them lantern slides of a dozen different kinds of germs; mysteriously he darkened the hall and suddenly shot a single bright beam of light through the blackness. “Observe the thousands of dancing specks of dust in the path of this ray,” he cried; “the air of this hall is filled with these specks of dust, these thousands of little nothings that you should not despise always, for sometimes they carry disease and death; the typhus, the cholera, the yellow fever and many other pestilences!” This was dreadful news; his audience shuddered, convinced by his sincerity. Of course this news was not strictly true, but Pasteur was no mountebank—he believed it himself! Dust and the microbes of the dust had become his life—he was obsessed with dust. At dinner, even at the smartest houses, he would hold his plates and spoons close up to his nose, peer at them, scour them with his napkin, he was with a vengeance putting microbes on the map....

Every Frenchman from the Emperor down was becoming excited about Pasteur and his microbes. Whisperings of mysterious and marvelous events seeped through the gates of the Normal School. Students, even professors, passed the laboratory a little atremble with awe. One student might be heard remarking to another, as they passed the high gray walls of the Normal School in the Rue d’Ulm: “There is a man working here—his name is Pasteur—who is finding out wonderful things about the machinery of life, he knows even about the origin of life, he is even going to find out, perhaps, what causes disease....” So Pasteur succeeded in getting another year added to the course of scientific studies; new laboratories began to go up; his students shed tears of emotion at the fiery eloquence of his lectures. He talked about microbes causing disease long before he knew anything about whether or not they caused disease—he hadn’t yet got his fingers at the throats of mysterious plagues and dreadful deaths, but he knew there were other ways to interest the public, to arouse even such a hardheaded person as the average Frenchman.

“I beg you,” he addressed the French people in a passionate pamphlet, “take some interest in those sacred dwellings meaningly called laboratories. Ask that they be multiplied and completed. They are the temples of the future, of riches and comfort.” Fifty years ahead of his time as a forward-looking prophet, he held fine austere ideals up to his countrymen while he appealed to their wishes for a somewhat piggish material happiness. A good microbe hunter, he was much more than a mere wool-gathering searcher, much more than a mere man of science....

Once more he started out to show all of France how science could save money for her industry; he packed up boxes of glassware and an eager assistant, Duclaux, and bustled off to Arbois, his old home—he hurried off up there to study the diseases of wine—to save the imperiled wine industry. He set up his laboratory in what had been an old café and instead of gas burners he had to be satisfied with an open charcoal brazier that the enthusiastic Duclaux kept glowing with a pair of bellows; from time to time Duclaux would scamper across to the town pump for water; their clumsy apparatus was made by the village carpenter and tinsmith. Pasteur rushed around to his friends of long ago and begged bottles of wine, bitter wine, ropy wine, oily wine; he knew from his old researches that it was yeasts that changed grapejuice into wine—he felt certain that it must be some other wee microscopic being that made wines go bad.

Sure enough! When he turned his lens on to ropy wines he found them swarming with very tiny curious microbes hitched together like strings of beads; he found the bottles of bitter wine infested with another kind of beast and the kegs of turned wine by still another. Then he called the winegrowers and the merchants of the region together and proceeded to show them magic.

“Bring me a half dozen bottles of wine that has gone bad with different sicknesses,” he asked them. “Do not tell me what is wrong with them, and I’ll tell you what ails them without tasting them.” The winegrowers didn’t believe him; among each other they snickered at him as they went to fetch the bottles of sick wine; they laughed at the fantastic machinery in the old café; they took Pasteur for some kind of earnest lunatic. They planned to fool him and brought him bottles of perfectly good wine among the sick ones. Then he set about flabbergasting them! With a slender glass tube he sucked a drop of wine out of a bottle and put it between two little slips of glass before his microscope. The wine raisers nudged each other and winked French winks of humorous common sense, while Pasteur sat hunched over his microscope, and they became more merry as minutes passed....

Suddenly he looked at them and said: “There is nothing the matter with this wine—give it to the taster—let him see if I’m right.”

The taster did his tasting, then puckered up his purple nose and admitted that Pasteur was correct; and so it went through a long row of bottles—when Pasteur looked up from his microscopes and prophesied: “Bitter wine”—it turned out to be bitter; and when he foretold that the next sample was ropy, the taster acknowledged that ropy was right!

The wine raisers mumbled their thanks and lifted their hats to him as they left. “We don’t get the way he does this—but he is a very clever man, very, very clever,” they muttered. That is much for a peasant Frenchman to admit....

When they left, Pasteur and Duclaux worked triumphantly in their tumbledown laboratory; they tackled the question of how to keep these microbes out of healthy wines—they found at last that if you heat wine just after it has finished fermenting, even if you heat it gently, way below the point of boiling, the microbes that have no business in the wine will be killed—and the wine will not become sick. That little trick is now known to everybody by the name of pasteurization.

Now that people of the East of France had been shown how to keep their wine from going bad, the people of the middle of France clamored for Pasteur to come and save their vinegar-making industry. So he rushed down to Tours. He had got used to looking for microscopic beings in all kinds of things by now—he no longer groped as he had had to do at first; he approached the vinegar kegs, where wine was turning itself into vinegar, he saw a peculiar-looking scum on the surface of the liquor in the barrels. “That scum has to be there, otherwise we get no vinegar,” explained the manufacturers. In a few weeks of swift, sure-fingered investigation that astonished the vinegar-makers and their wives, Pasteur found that the scum on the kegs was nothing more nor less than billions upon billions of microscopic creatures. He took off great sheets of this scum and tested it and weighed it and fussed with it, and at last he told an audience of vinegar-makers and their wives and families that the microbes which change wine to vinegar actually eat up and turn into vinegar ten thousand times their own weight of alcohol in a few days. What gigantic things these infinitely tiny beings can do—think of a man of two hundred pounds chopping two millions of pounds of wood in four days! It was by some such homely comparison as this one that he made microbes part of these humble people’s lives, it was so that he made them respect these miserably small creatures; it was by pondering on their fiendish capacity for work that Pasteur himself got used to the idea that there was nothing so strange about a tiny beast, no larger than the microbe of vinegar, getting into an ox or an elephant or a man—and doing him to death. Before he left them he showed the people of Tours how to cultivate and care for those useful wee creatures that so strangely added oxygen to wine to turn it into vinegar—and millions of francs for them.

These successes made Pasteur drunk with confidence in his method of experiment; he began to dream impossible gaudy dreams—of immense discoveries and super-Napoleonic microbe huntings—and he did more than brood alone over these dreams; he put them into speeches and preached them. He became, in a word, a new John the Baptist of the religion of the Germ Theory, but unlike the unlucky Baptist, Pasteur was a forerunner who lived to see at least some of his prophecies come true.

Then for a short time he worked quietly in his laboratory in Paris—there was nothing for him to save just then—until one day in 1865 Fate came to his door and knocked. Fate in the guise of his old professor, Dumas, called on him and asked him to change himself from a man of science into a silkworm doctor. “What’s wrong with silkworms? I did not know that they ever had diseases—I know nothing at all about silkworms—what’s more, I have never even seen one!” protested Pasteur.

VI

“The silk country of the South is my native country,” answered Dumas. “I’ve just come back from there—it is terrible—I cannot sleep nights for thinking of it, my poor country, my village of Alais.... This country that used to be rich, that used to be gay with mulberry trees which my people used to call the Golden Tree—this country is desolate now. The lovely terraces are going to ruin—the people, they are my people, they are starving....” Tears were in his voice.

Anything but a respecter of persons, Pasteur who loved and respected himself above all men, had always kept a touching reverence for Dumas. He must help his sad old professor! But how? It is doubtful at this time if Pasteur could have told a silkworm from an angle worm! Indeed, a little later, when he was first given a cocoon to examine, he held it up to his ear, shook it, and cried: “Why, there is something inside it!” Pasteur hated to go South to try to find out what ailed silkworms, he knew he risked a horrid failure by going and he detested failure above everything. But it is one of the charming things about him that in the midst of all his arrogance, his vulgar sureness of himself, he had kept that boyish love and reverence for his old master—so he said to Dumas: “I am in your hands, I’m at your disposal, do with me as you wish—I will go!”

So he went. He packed up the never complaining Madame Pasteur and the children and a microscope and three energetic and worshiping young assistants and he went into the epidemic that was slaughtering millions of silkworms and ruining the South of France. Knowing less of silkworms and their sicknesses than a babe in swaddling clothes he arrived in Alais; he got there and he learned that a silkworm spins a cocoon round itself and turns into a chrysalid inside the cocoon; he found out that the chrysalid changes into a moth that climbs out and lays eggs—which hatch out the next spring into new broods of young silkworms. The silkworm growers—disgusted at his great ignorance—told him that the disease which was killing their worms was called pébrine, because the sick worms were covered with little black spots that looked like pepper. Pasteur found out that there were a thousand or so theories about the sickness, but that the little pepper spots—and the curious little globules inside the sick worms, wee globules that you could only see with a microscope—were the only facts that were known about it.

Then Pasteur unlimbered his microscope, before he had got his family settled—he was like one of those trout fishing maniacs who starts to cast without thought of securing his canoe safely on the bank—he unlimbered his microscope, I say, and began to peer at the insides of sick worms, and particularly at these wee globules. Quickly he concluded that the globules were a sure sign of the disease. Fifteen days after he had come to Alais he called the Agricultural Committee together and told them: “At the moment of egg-laying put aside each couple of moths, the father and the mother. Let them mate; let the mother lay her eggs—then pin the father and mother moths down onto a little board, slit open their bellies and take out a little of the fatty tissue under their skin; put this under a microscope and look for those tiny globules. If you can’t find any, you can be sure the eggs are sound—you can use those eggs for new silkworms in the spring.”

The committee looked at the shining microscope. “We farmers can’t run a machine like that,” they objected. They were suspicious, they didn’t believe in this newfangled machine. Then the salesman that was in Pasteur came to the front. “Nonsense!” he answered. “There is an eight-year-old girl in my laboratory who handles this microscope easily and is perfectly able to spot these little globules—these corpuscles—and then you grown men try to tell me you couldn’t learn to use a microscope!” So he shamed them. And the committee obediently bought microscopes and tried to follow his directions. Then Pasteur started a hectic life; he was everywhere around the tragic silk country, lecturing, asking innumerable questions, teaching the farmers to use microscopes, rushing back to the laboratory to direct his assistants—he directed them to do complicated experiments that he hadn’t time to do, or even watch, himself—and in the evenings he dictated answers to letters and scientific papers and speeches to Madame Pasteur. The next morning he was off again to the neighboring towns, cheering up despairing farmers and haranguing them....

But the next spring his bubble burst, alas. The next spring, when it came time for the worms to climb their mulberry twigs to spin their silk cocoons, there was a horrible disaster. His confident prophecy to the farmers did not come true. These honest people glued their eyes to their microscopes to pick out the healthy moths, so as to get healthy eggs, eggs without the evil globules in them—and these supposed healthy eggs hatched worms, sad to tell, who grew miserably, languid worms who would not eat, strange worms who failed to molt, sick worms who shriveled up and died, lazy worms who hung around at the bottoms of their twigs, not caring whether there was ever another silk stocking on the leg of any fine lady in the world.

Poor Pasteur! He had been so busy trying to save the silkworm industry that he hadn’t taken time to find out what really ailed the silkworms. Glory had seduced him into becoming a mere savior—for a moment he forgot that Truth is a will o’ the wisp that can only be caught in the net of glory-scorning patient experiment....

Some silkworm raisers laughed despairing laughs at him—others attacked him bitterly; dark days were on him. He worked the harder for them, but he couldn’t find bottom. He came on broods of silkworms who fairly galloped up the twigs and proceeded to spin elegant cocoons—then at the microscope he found these beasts swarming with the tiny globules. He discovered other broods that sulked on their branches and melted away with a gassy diarrhœa and died miserably—but in these he could find no globules whatever. He became completely mixed up; he began to doubt whether the globules had anything to do with the disease. Then to make things worse, mice got into the broods of his experimental worms and made cheerful meals on them and poor Duclaux, Maillot and Gernez had to stay up by turns all night to catch the raiding mice; next morning everybody would be just started working when black clouds appeared in the West, and all of them—Madame Pasteur and the children bringing up the rear—had to scurry out to cover up the mulberry trees. In the evenings Pasteur had to settle his tired back in an armchair, to dictate answers to peeved silkworm growers who had lost everything—using his method of sorting eggs.

After a series of such weary months, his instinct to do experiments, this instinct—and the Goddess of Chance—came together to save him. He pondered to himself: “I’ve at least managed to scrape together a few broods of healthy worms—if I feed these worms mulberry leaves smeared with the discharges of sick worms, will the healthy worms die?” He tried it, and the healthy worms died sure enough, but, confound it! the experiment was a fizzle again—for instead of getting covered with pepper spots and dying slowly in twenty-five days or so, as worms always do of pébrine—the worms of his experiment curled up and passed away in seventy-two hours. He was discouraged, he stopped his experiments; his faithful assistants worried about him—why didn’t he try the experiment over?

At last Gernez went off to the north to study the silk worms of Valenciennes, and Pasteur, not clearly knowing the reason why, wrote to him and asked him to do that feeding experiment up there. Gernez had some nice broods of healthy worms. Gernez was sure in his own head—no matter what his chief might think—that the wee globules were really living things, parasites, assassins of the silkworm. He took forty healthy worms and fed them on good healthy mulberry leaves that had never been fed on by sick beasts. These worms proceeded to spin twenty-seven good cocoons and there were no globules in the moths that came from them. He smeared some other leaves with crushed-up sick moths and fed them to some day-old worms—and these worms wasted away to a slow death, they became covered with pepper spots and their bodies swarmed with the sub-visible globules. He took some more leaves with crushed-up sick moths and fed these to some old worms just ready to spin cocoons; the worms lived to spin the cocoons, but the moths that came out of the cocoons were loaded with the globules, and the worms from their eggs came to nothing. Gernez was excited—and he became more excited when still nights at his microscope showed him that the globules increased tremendously as the worms faded to their deaths....

Gernez hurried to Pasteur. “It is solved,” he cried, “the little globules are alive—they are parasites!—They are what make the worms sick!”

It was six months before Pasteur was convinced that Gernez was right, but when at last he understood, he swooped back on his work, and once more called the Committee together. “The little corpuscles are not only a sign of the disease, they are its cause. These globules are alive, they multiply, they force themselves into every part of the moth’s body. Where we made our mistake was to examine only a little part of the moth, we only looked under the skin of the moth’s belly—we’ve got to grind up the whole beast and examine all of it. Then if we do not find the globules we can safely use the eggs for next year’s worms!”

The committee tried the new scheme and it worked—the next year they had fine worms that gave them splendid yields of silk.

Pasteur saw now that the little globule, the cause of the pébrine, came from outside the worm—it did not rise by itself inside the worm—and he went everywhere, showing the farmers how to keep their healthy worms away from all contact with leaves that sick worms had soiled. Then suddenly he fell a victim of a hemorrhage of the brain—he nearly died, but when he heard that work of building his new laboratory had been stopped, frugally stopped in expectation of his death, he was furious and made up his mind to live. He was paralyzed on one side after that—he never got over it—but he earnestly read Dr. Smiles’ book, “Self Help,” and vigorously decided to work in spite of his handicap. At a time when he should have stayed in his bed, or have gone to the seaside, he staggered to his feet and limped to the train for the South, exclaiming indignantly that it would be criminal not to finish saving the silkworms while so many poor people were starving! All Frenchmen, excepting a few nasty fellows who called it a magnificent gesture, joined in praising him and adoring him.

For six years Pasteur struggled with the diseases of silkworms. He had no sooner settled pébrine than another malady of these unhappy beasts popped up, but he knew his problem and found the microbe of this new disease much more quickly. Tears of joy were in the voice of old Dumas now as he thanked his dear Pasteur—and the mayor of the town of Alais talked enthusiastically of raising a golden statue to the great Pasteur.

VII

He was forty-five. He wallowed in this glory for a moment, and then—having saved the silkworm industry, with the help of God and Gernez—he raised his eyes toward one of those bright, impossible, but always partly true visions that it was his poet’s gift to see. He raised his artist’s eyes from the sicknesses of silkworms to the sorrows of men, he sounded a trumpet call of hope to suffering mankind:

“It is in the power of man to make parasitic maladies disappear from the face of the globe, if the doctrine of spontaneous generation is wrong, as I am sure it is.”

The siege of Paris in the bitter winter of 1870 had driven him from his work to his old home in the Jura hills. He wandered pitifully around battlefields looking for his son who was a sergeant. Here he worked himself up into a tremendous hate, a hate that never left him, of all things German; he became a professional patriot. “Every one of my works will bear on its title page, ‘Hatred to Prussia. Revenge! Revenge!’” he shrieked, good loyal Frenchman that he was. Then with a magnificent silliness he proceeded to make his next research a revenge research. Even he had to admit that French beer was much inferior to the beer of the Germans. Well—he would make the beer of France better than the beer of Germany—he must make the French beer the peer of beers, no, the emperor of all beers of the world!

He embarked on vast voyages to the great breweries of France and here he questioned everybody from the brewmaster in his studio to the lowest workman that cleaned out the vats. He journeyed to England and gave advice to those red-faced artists who made English porter and to the brewers of the divine ale of Bass and Burton. He trained his microscope on the must of a thousand beer vats to watch the yeast globules at their work of budding and making alcohol. Sometimes he discovered the same kind of miserable sub-visible beings that he had found in sick wines years before, and he told the brewers that if they would heat their beer, they would keep these invaders out; he assured them that then they would be able to ship their beer long distances, that then they would be able to brew the most incredibly marvelous of all beers! He begged money for his laboratory from brewers, explaining to them how they would be repaid a thousand fold, and with this money he turned his old laboratory at the Normal School into a small scientific brewery that glittered with handsome copper vats and burnished kettles.

But in the midst of all this feverish work, alas, Pasteur grew sick of working on beer. He hated the taste of beer just as he loathed the smell of tobacco smoke; to his disgust he found that he would have to become a good beer-taster in order to become a great beer-scientist, to his dismay he discovered that there was much more to the art of brewing than simply keeping vicious invading microbes out of beer vats. He puckered his snub nose and buried his serious mustache in foamy mugs and guzzled determined draughts of the product of his pretty kettles—but he detested this beer, even good beer, in fact all beer. Bertin, the physics professor, his old friend, smacked his lips and laughed at him as he swallowed great gulps of beer that Pasteur had denounced as worthless. Even the young assistants snickered—but never to his face. Pasteur, most versatile of men, was after all not a god. He was an investigator and a marvelous missionary—but beer-loving is a gift that is born in a limited number of connoisseurs, just as the ear for telling good music from trash is born in some men!

Pasteur did help the French beer industry. For that we have the testimony of the good brewers themselves. It is my duty to doubt, however, the claims of those idolizers of his who insist that he made French the equal of German beer. I do not deny this claim, but I beg that it be submitted to a commission, one of those solemn impartial international commissions, the kind of commission that Pasteur himself so often demanded to decide before all the world whether he or his detested opponents were in the right....

Pasteur’s life was becoming more and more unlike the austere cloistered existence that most men of science lead. His experiments became powerful answers to the objections that swarmed on every side against his theory of germs, they became loud public answers to such objections—rather than calm quests after facts; but in spite of his dragging science into the market place, there is no doubt that his experiments were marvelously made, that they fired the hopes and the imagination of the world. He got himself into a noisy argument on the way yeasts turn grape juice into wine, with two French naturalists, Frémy and Trécul. Frémy admitted that yeasts were needed to make alcohol from grape juice, but he argued ignorantly before the amused Academy that yeasts were spontaneously generated inside of grapes. The wise men of the Academy pooh-poohed; they were amused, all except Pasteur.

“So Frémy says that yeasts rise by themselves inside the grape!” cried Pasteur. “Well, let him answer this experiment then!” He took a great number of round-bellied flasks and filled them part full of grape juice. He drew each one out into a swan’s neck; then he boiled the grape juice in all of them for a few minutes and for days and weeks this grape juice, in every one of all these flasks, showed no bubbles, no yeasts, there was no fermentation in them. Then Pasteur went to a vineyard and gathered a few grapes—they were just ripe—and with a pure water he washed the outsides of them with a clean, heated, badger hairbrush. He put a drop of the wash water under his lens—sure enough!—there were globules, a few wee globes, of yeasts. Then he took ten of his swan neck flasks and ingeniously sealed straight tubes of glass into their sides, and through these straight tubes in each one he put a drop of this wash water from the ripe grapes. Presto! Every one of these ten flasks was filled to the neck in a few days with the pink foam of a good fermentation. There was a little of the wash water left; he boiled that and put drops of this through the straight tubes of ten more flasks. “Just so!” he cried a few days later, “there’s no fermentation in these flasks, the boiling has killed the yeasts in the wash water.”

“Now I shall do the most remarkable experiment of all—I’ll prove to this ignorant Frémy that there are no yeasts inside of ripe grapes,” and he took a little hollow tube with a sharp point, sealed shut; it was a little tube he had heated very hot in an oven to kill all life—all yeasts—that might have been in it. Carefully he forced the sharp closed point of the tube through the skin into the middle of the grape; delicately he broke the sealed tip inside the grape—and the little drop of juice that welled up into the tube he transferred with devilish cunning into another swan-necked flask part filled with grape juice. A few days later he cried, “That finishes Frémy—there is no fermentation in this flask at all—there is no yeast inside the grape!” He went on to one of those sweeping statements he loved to make: “Microbes never rise by themselves inside of grapes, or silkworms, or inside of healthy animals—in animal’s blood or urine. All microbes have to get in from the outside! That settles Frémy.” Then you can fancy him whispering to himself: “The world will soon learn the miracles that will grow from this little experiment.”

VIII

Surely it looked then as if Pasteur had a right to his fantastic dreams of wiping out disease. He had just received a worshiping letter from the English surgeon Lister—and this letter told of a scheme for cutting up sick people in safety, of doing operations in a way that kept out that deadly mysterious infection that in many hospitals killed eight people out of ten. “Permit me,” wrote Lister, “to thank you cordially for having shown me the truth of the theory of germs of putrefaction by your brilliant researches, and for having given me the single principle which has made the antiseptic system a success. If you ever come to Edinburgh it will be a real recompense to you, I believe, to see in our hospital in how large a measure humanity has profited from your work.”

Like a boy who has just built a steam engine all by himself Pasteur was proud; he showed the letter to all his friends; he inserted it with all its praise in his scientific papers; he published it—of all places—in his book on beer! Then he took a final smash at poor old Frémy, who you would have thought was already sufficiently crushed by the gorgeous experiments; he smashed Frémy not by damning Frémy, but by praising himself! He spoke of his own “remarkable discoveries,” he called his own theories the true ones and ended: “In a word, the mark of true theories is their fruitfulness. This is the characteristic which Mr. Balard, with an entirely fatherly friendliness, has made stand out in speaking of my researches.” Frémy had no more to say.

All Europe by now was in a furor about microbes, and he knew it was himself that had changed microbes from playthings into useful helpers of mankind—and perhaps, the world would soon be astounded by it—into dread infinitesimal ogres and murdering marauders, the worst enemies of the race. He had become the first citizen of France and even in Denmark prominent brewers were having his bust put in their laboratories. When suddenly Claude Bernard died, and some of Bernard’s friends published this great man’s unfinished work. Horrible to tell, this unfinished work had for its subject fermentation of grape juice into wine, and it ended by showing that the whole theory of Pasteur was destroyed because ... and Bernard closed by giving a series of reasons.

Pasteur could not believe his eyes. Bernard had done this, the great Bernard who had been his seatmate in the Academy and had always praised his work; Bernard who had exchanged sly sarcastic remarks with him at the Academy of Medicine about those blue-coated pompous brass-buttoned doctors whose talk was keeping real experiment out of medicine. “It’s bad enough for these doctors and these half-witted naturalists to contradict me—but truly great men have always appreciated my work—and now Bernard ...” you can hear him muttering.

Pasteur was overwhelmed, but only for a moment. He demanded Bernard’s original manuscript. They gave it to him. He studied it with all the close attention in his power. He found Bernard’s experiments were only beginnings, rough sketches; gleefully he found that Bernard’s friends who had published it had made some discreet changes to make it read better. Then he rose one day, to the scandal of the entire Academy and the shocked horror of all the great men of France, and bitterly scolded Bernard’s friends for publishing a research that had dared to question his own theories. Vulgarly he shouted objections at Bernard—who, after all, could not answer Pasteur from his grave. Then he published a pamphlet against his old dead friend’s last researches. It was a pamphlet in the worst of taste, accusing Bernard of having lost his memory. That pamphlet even claimed that Bernard, who was to his finger tips a hard man of science, had become tainted with mystical ideas by associating too much with literary lights of the French Academy. It even proved that in his last researches Bernard couldn’t see well any more—“I’ll wager he had become farsighted and could not see the yeasts!” cried Pasteur. Vulgarly, by all this criticism, he left people to conclude that Bernard had been in his dotage when he did his last work—without any sense of the fitness of things this passionate Pasteur jumped up and down on Bernard’s grave.

Finally he argued with Bernard by beautiful experiments—a thing most other men would have done without making unseemly remarks. Like an American about to build a skyscraper in six weeks he rushed to carpenters and hardware stores and bought huge pieces of expensive glass and with this glass he had the carpenters build ingenious portable hothouses. His assistants worked dinnerless and sleepless, preparing flasks and microscopes and wads of heated cotton; and in an unbelievably short time Pasteur gathered up all this ponderous paraphernalia and hastened to catch a train for his old home in the Jura mountains. Like the so typical misplaced American that he really was, he threw every consideration and all other work to the winds and went directly to the point of settling: “Does my theory of fermentation hold?”

Coming to his own little vineyard in Arbois, he hastily put up his hothouses around a part of his grape-vines. They were admirable close-fitting hothouses that sealed the grape-vines from the outside air. “It’s midsummer, now, the grapes are far from ripe,” he pondered, “and I know that at this time there are never any yeasts to be found on the grapes.” Then, to make doubly sure that no yeasts from the air could fall on the grapes, he carefully wrapped wads of cotton—which his assistants had heated to kill all living beings—around some of the bunches under the glass of the hothouses. He hurried back to Paris and waited nervously for the grapes to ripen. He went back to Arbois too soon in his frantic eagerness to prove that Bernard was wrong—but at last he got there to find them ripe. He examined the hothouse grapes with his microscope; there was not a yeast to be found on their skins. Feverishly he crushed some of them up in carefully heated bottles—not a single bubble of fermentation rose in these flasks—and when he did the same thing to the exposed grapes from the vines outside the hothouse, these bubbled quickly into wine! At last he gathered up Madame Pasteur and some of the vines with their cotton-wrapped bunches of grapes—he was going to take these back to the Academy, where he would offer a bunch to each member that wanted one, and he was going to challenge everybody to try to make wine from these protected bunches.... He knew they couldn’t do it without putting yeasts into them.... He would show them all Bernard was wrong! Madame Pasteur sat stiffly in the train all the way back to Paris, carefully holding the twigs straight up in front of her so that the cotton wrappings wouldn’t come undone. It was a whole day’s trip to Paris....

Then at the next meeting Pasteur told the Academy of how he had quarantined his grape-vines against yeasts: “Is it not worthy of attention,” he shouted, “that in this vineyard of Arbois, and this would be true of millions of acres of vineyards all over the world, there was at the moment I made these experiments, not a speck of soil which was not capable of fermenting grapes into wine; and is it not remarkable that, on the contrary, the soil of my hothouses could not do this? And why? Because at a definite moment, I covered this soil with some glass....”

Then he jumped to marvelous predictions, prophecies that have since his time come true, he leaped to poetry, I say, that makes you forget his vulgar wrangling with his dead friend Bernard. “Must we not believe, as well, that a day will come when preventive measures that are easy to apply, will arrest those plagues ...” and he painted them a lurid picture of the terrible yellow fever that just then had changed the gay streets of New Orleans into a desolation. He made them shiver to hear of the black plague on the far banks of the Volga. Finally he made them hope....

Meanwhile in a little village in Eastern Germany a young stubborn round-headed Prussian doctor was starting on his road to those very miracles that Pasteur was prophesying—this young doctor was doing strange experiments with mice in time stolen from his practice. He was devising ingenious ways to handle microbes so that he could be dead sure he was handling only one kind—he was learning to do a thing that Pasteur with all his brilliant skill had never succeeded in doing. Let us leave Pasteur for a while—even though he is on the threshold of his most exciting experiments and funniest arguments—let us leave him for a chapter and go with Robert Koch, while he is learning to do fantastic, and marvelously important things with those microbes which had been subjects of Pasteur’s kingdom for so many years.